DEC Indicator Panels page

Mike Ross tmfdmike at
Thu Aug 18 17:35:57 CDT 2016

On Fri, Aug 19, 2016 at 5:02 AM, Noel Chiappa <jnc at> wrote:
>     > From: Mattis Lind

> The other one seems to be the same as this one:
>     >
>     >
>     > The panel to the left is RF15 and the right is TC15. But what is the
>     > middle one?
> which is in quite a few PDP-15 images, but still un-identified.
> It seems to be always near the CPU, so perhaps it's a panel for the memory
> management, or something like that? I've looked through some of the manuals
> on BitSavers, and I've yet to turn it up, although the block diagram on page
> 2-3 of the PDP-15 Installation Manual shows an 'indicator [panel]' (no
> further info on it, alas) in that location, which is probably it.
> There aren't that many devices in that system, so there are only a few
> possibilities: BA15 (paper tape controller), DW15A (bus converter), KE15
> (extended arithmetic), MM15-A and MK15-A (memory). It might also be a BD15,
> whatever that might be (seems to include a D/A, from what little I can find
> on it online), since that was listed as having an insert for it.
>         Noel

I'm reasonably sure that's connected with the original PC15 high-speed
paper tape controller. On the XVM systems I have the paper tape
function is integrated in the BA15 Peripheral Expander (a small
collection of boards which lives at the bottom of the CPU rack) and
which doesn't have any indicator panel. I'm not aware of any memory
indicator panels associated with any pdp-15 configuration but I could
be wrong!

Oh and there's a better pic of the RF15/RF09 indicator panel in this

'No greater love hath a man than he lay down his life for his brother.
Not for millions, not for glory, not for fame.
For one person, in the dark, where no one will ever know or see.'

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